Its flowers are visited by birds and bats, and it serves as a roosting site and food source for a variety of animals.

Roystonea regia is the national tree of Cuba,[6] and has a religious role both in Santería and Christianity, where it is used in Palm Sunday observances.

)[8] The trunk is stout, very smooth and grey-white in colour with a characteristic bulge below a distinctive green crownshaft.

[10] In addition to evidence of nitrogen fixation, the nodules were also found to be producing indole acetic acid, an important plant hormone.

[14] As of 2008, there appear to be no molecular phylogenetic studies of Roystonea[13] and the relationship between R. regia and the rest of the genus is uncertain.

The species was first described by American naturalist William Bartram in 1791 as Palma elata based on trees growing in central Florida.

[9] In 1816 German botanist Carl Sigismund Kunth described the species Oreodoxa regia[3] based on collections made by Alexander von Humboldt and Aimé Bonpland in Cuba.

[15] In 1825 German botanist Curt Polycarp Joachim Sprengel moved it to the genus Oenocarpus and renamed it O. regius.

[3] In 1906 Charles Henry Wright described two new species based on collections from Georgetown, British Guiana (now Guyana) which he placed in the genus Euterpe — E. jenmanii and E. ventricosa.

Bartram applied the Linnaean binomial Palma elata to a "large, solitary palm with an ashen white trunk topped by a green leaf sheath [the crownshaft] and pinnate leaves"[20] growing in central Florida.

[21] In Cambodia, where it is planted as decorative along avenues and in public parks, it is known as sla barang' ("Western palm").

[25] Roystonea regia is found in Central America, Cuba, the Cayman Islands, Hispaniola (the Dominican Republic and Haiti), the Lesser Antilles, The Bahamas, southern Florida, and Mexico (in Veracruz, Campeche, Quintana Roo, and Yucatán).

[7] Royal Palm State Park in the Everglades was established due to the high concentration of the species.

[28] Roystonea is cultivated in tropical and subtropical climates in the United States, Australia, Brazil, and parts of southern Asia as a landscape palm.

[31] In Panama (where R. regia is introduced), its trunks are used as nesting sites by yellow-crowned parrots (Amazona ochrocephala panamensis).

[7] Roystonea regia is the host plant for the royal palm bug, Xylastodoris luteolus, in Florida.

[33] It also serves as a larval host plant for the butterflies Pyrrhocalles antiqua orientis and Asbolis capucinus in Cuba,[34] and Brassolis astyra and B. sophorae in Brazil.

[35] It is susceptible to bud rot caused by the oomycete Phytophthora palmivora[36] and by the fungus Thielaviopsis paradoxa.